No, thats not a particularly big head. Its perspective distortion created by ultra wide angles lenses on SLR cameras when they are focused on nearby subjects. What is near looks much much bigger than what's far. Try to imagine your favorite landscape photograph. A 50mm lens on 35 mm cameras would have almost zero exaggeration, and telephoto lenses have the reverse effect (perspective compression).
Now having said that, he still seems to have a bigger than normal head.